Toothy tormentors beyond the Tidal Basin

Comment

May 16, 1999|By Mike Burns

PLENTY OF beaver here, but no complaints about them. That's the word from Carroll County nature centers and the Humane Society. The buck-toothed buzz saws are happily proliferating in the reservoirs and streams throughout the county.

Beaver problems are cropping up all over the state and nation -- in Glen Burnie, Aberdeen Proving Ground, Columbia, Washington's Tidal Basin, for example. It's just a matter of time before these voracious 50-pound rodents become a pest in Carroll.

Flooded roadways, woodlands and back yards, shoreline erosion, loss of fish habitat -- these are some of the damage inflicted by busy beavers. To say nothing of chewing down ornamental trees and changing the riverine ecology.

Nearly extinct in Maryland 50 years ago, the beaver have made a stupendous comeback through wildlife restoration efforts -- and an incredible ability to reproduce and adapt throughout Maryland.

Over the past decade, the beaver population in this state has tripled, estimates Robert Colona, a Department of Natural Resources expert. They are well established in every county.

"They've occupied all the primary habitat. They've occupied all the secondary habitat. Now they're spreading into marginal habitat, like suburban storm water ponds," Mr. Colona said.

"They're close to the carrying capacity," he said.

That's meant more trapping of the animals as nuisances, even as slumping prices on the world fur market have discouraged more intensive wintertime trapping for pelts. Much of the beaver trapping in Maryland is done as a family cultural tradition passed down by generations; but that impact on beaver control is limited without economic incentives.

The private trappers "remove" nuisance beaver from private property, which means the animal is destroyed. There's no place to relocate beavers without transferring the problem elsewhere. High numbers and greater competition for habitat among the paddle-tails makes relocation problematic. They have no natural predators here, except for man.

But there's another way to look at beaver, one the state agency is trying to promote. Beavers can be a positive wildlife experience, not only for their own interesting activities but for the new birds and wildlife attracted by the ponds they create with their dams.

"They are not bad animals. They just do what beavers naturally do," says Kenneth D'Loughy, DNR's manager for the Central Maryland region, which includes Carroll. "They are important from an ecological standpoint."

`Beaver deceivers'

Human precautions can minimize some beaver problems, he pointed out. Hardware cloth or welded wire mesh encircling valuable ornamental trees can deter the ravenous rodents, who fell the trees for damming streams and for the inner bark (cambium) which is their favored food. Dam-breaching baffle pipes ("beaver deceivers") can preserve beaver habitat while lowering water levels to lessen the threat of flooding.

"It depends on what people are prepared to accept," Mr. D'Loughy said.

On a recent nature hike along the northern Gunpowder River, DNR's Suzanne Bates pointed out beaver colonies to an enthusiastic crowd. It's part of DNR's effort to educate the public about the animal.

"Beaver really are interesting creatures, and they can do good things in the right places," the ranger said.

Marvel on the Gunpowder

You could hear the cries of children as they spotted their first beaver, swimming toward them with branch clenched in his teeth, the distinctive broad tail visible in the clear water.

You could see the wonder on the faces of adults as they pondered the industriousness of the animal repairing some piece of the mound of sticks that covers its lodge. Spotting the next beaver and his lodge brought excited smiles to the faces of hikers.

If beavers were confined to parks and wildlands, they'd be little problem, but they persistently encroach into human environment, Mr. D'Loughy noted. Some states and private land owners offer bounties on beaver, the U.S. Department of Agriculture runs a busy beaver control program.

"The trouble is that people think of beavers as soft and cuddly, but they're not," Mr. Colona observed. Their powerful teeth and sharp claws can inflict heavy damage; constant bloody battles over territory leave many of the beavers badly injured. The average age of a beaver here is only about 2 years because of the competition, though they can live as long as 10 years. Two-year-olds are fiercely driven from the lodge and must find a new home far enough away to avoid conflict.

Some Carroll landowners have had beavers removed because of flooded woodlands and steambanks, but they are not yet a serious menace in these parts.

As Piney Run Park naturalist Deanna Hofmann remarked: "People don't complain about the beaver, they want to see them."